class_docstr: DistributedImageSet wraps an RDD of ImageFeature
docstr: get label rdd from ImageSet
docstr_tok: ["get","label","rdd","from","ImageSet"]
code: def get_label(self):
      """
      get label rdd from ImageSet
      """
      tensor_rdd = callZooFunc(
          self.bigdl_type,
          "distributedImageSetToLabelTensorRdd",
          self.value,
      )
      return tensor_rdd.map(lambda tensor: tensor.to_ndarray())
  
imports: from bigdl.transform.vision.image import ImageFrame
  from bigdl.util.common import *
  from zoo.common.utils import callZooFunc
label_desc: Use image node_id 3 for calling the DistributedImageSet obj's underlying member method code with example usage: obj.get_label() and returns: tensor_rdd